Tourette Syndrome (TS) is a neurological disorder characterized by persistent motor and vocal tics. Tics can be brief, rapid and darting movements of the face, shoulders, and extremities or more complex and purposeful in appearance. Vocal tics can be simple sounds such as sniffing or grunting or more complex sounds including repeated words and phrases. Tics wax and wane over time with peak severity between ages 10 and 12 years. However, some individuals have a more enduring course of tics into adulthood. When present in adults, the tics of TS can be associated with considerable distress, social and occupational impairment, and discrimination. A substantial body of evidence implicates dysfunction of cortical-subcortical pathways involving the thalamus, basal ganglia and the frontal cortex. Although neurologically-based, behavioral and environmental factors may also play a role in tic maintenance. Currently, the standard treatment for tic suppression is medication, particularly centrally acting dopamine-blocking drugs. However, these medications are associated with a range of adverse effects that can result in poor compliance or in premature termination of treatment. Moreover, currently available medications rarely eliminate all tics. Thus, when managing their chronic condition, adults are often faced with a partial response to medication, or they opt to avoid all medications due to unacceptable side effects. Preliminary research by the investigators listed on this application suggests that a behavioral treatment called habit reversal training (HRT) is a promising intervention for tics. HRT is a multi-component treatment approach that includes awareness training, selfmonitoring, contingency management, inconvenience review, relaxation training and competing responses. HRT is designed as a monotherapy and/or as an augmentation to pharmacotherapy. Although the initial studies evaluating the efficacy of HRT in TS have been encouraging, to date the investigations have been case studies or small randomized trials, and HRT has never been systematically investigated as an augmentation to pharmacotherapy. In response to Program Announcement PA 01-123, this application describes a multisite investigation to evaluate the efficacy of a structured HRT program for tic reduction in adults with TS. To conduct this study, the Tourette Syndrome Association (TSA) assembled the Behavioral Sciences Consortium (BSC). The BSC is a multidisciplinary group of investigators representing some of the leading TS research programs in the country including Yale, Massachusetts General Hospital (MGH)/Harvard Medical School, University of California at Los Angeles (UCLA), and Johns Hopkins. Two additional centers, Wilford Hall Medical Center/University of Texas Health Sciences Center at San Antonio (WHMC/UTHSCSA), and the University of Wisconsin-Milwaukee (UWM), have investigators with specific expertise in HRT. The mission of the BSC is to develop, test, and disseminate behavioral interventions for patients with TS. In this proposed study, 120 eligible participants will be randomly assigned to receive either HRT or Enhanced- Supportive Psychotherapy. Both treatments will consist of 10 sessions over 12 weeks followed by 2 booster sessions and 3- and 6-months follow up assessments. The primary outcome of interest will be change in tic severity assessed by an independent evaluator blind to treatment assignment. The effect of HRT as a monotherapy for tics and as augmentation to ongoing, stable tic-suppressing medication will also be evaluated. The three study recruitment sites are MGH/Harvard, WHMC/UTHSCSA, and Yale University. Investigators from UCLA and the UWM will provide specific quality assurance and assessment services via separate subcontracts, and a Data Safety and Monitoring Board (DSMB) will be assembled for data and safety monitoring purposes. The Informatics group at Yale University will provide data management services.